/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.formats.avro;

import org.apache.flink.annotation.PublicEvolving;
import org.apache.flink.api.common.serialization.DeserializationSchema;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.formats.avro.typeutils.AvroSchemaConverter;
import org.apache.flink.table.data.RowData;
import org.apache.flink.table.types.logical.RowType;

import org.apache.avro.generic.GenericRecord;

import javax.annotation.Nullable;

import java.io.IOException;
import java.util.Objects;

/**
 * Deserialization schema from Avro bytes to {@link RowData}.
 *
 * <p>Deserializes the <code>byte[]</code> messages into (nested) Flink RowData. It converts Avro
 * types into types that are compatible with Flink's Table & SQL API.
 *
 * <p>Projects with Avro records containing logical date/time types need to add a JodaTime
 * dependency.
 *
 * <p>Note: Changes in this class need to be kept in sync with the corresponding runtime class
 * {@link AvroRowDataSerializationSchema} and schema converter {@link AvroSchemaConverter}.
 */
@PublicEvolving
public class AvroRowDataDeserializationSchema implements DeserializationSchema<RowData> {

    private static final long serialVersionUID = 1L;

    /** Nested schema to deserialize the inputs into avro {@link GenericRecord}. * */
    private final DeserializationSchema<GenericRecord> nestedSchema;

    /** Type information describing the result type. */
    private final TypeInformation<RowData> typeInfo;

    /** Runtime instance that performs the actual work. */
    private final AvroToRowDataConverters.AvroToRowDataConverter runtimeConverter;

    /**
     * Creates a Avro deserialization schema for the given logical type.
     *
     * @param rowType The logical type used to deserialize the data.
     * @param typeInfo The TypeInformation to be used by {@link
     *     AvroRowDataDeserializationSchema#getProducedType()}.
     */
    public AvroRowDataDeserializationSchema(RowType rowType, TypeInformation<RowData> typeInfo) {
        this(
                AvroDeserializationSchema.forGeneric(AvroSchemaConverter.convertToSchema(rowType)),
                AvroToRowDataConverters.createRowConverter(rowType),
                typeInfo);
    }

    /**
     * Creates a Avro deserialization schema for the given logical type.
     *
     * @param nestedSchema Deserialization schema to deserialize as {@link GenericRecord}
     * @param runtimeConverter Converter that transforms a {@link GenericRecord} into {@link
     *     RowData}
     * @param typeInfo The TypeInformation to be used by {@link
     *     AvroRowDataDeserializationSchema#getProducedType()}
     */
    public AvroRowDataDeserializationSchema(
            DeserializationSchema<GenericRecord> nestedSchema,
            AvroToRowDataConverters.AvroToRowDataConverter runtimeConverter,
            TypeInformation<RowData> typeInfo) {
        this.nestedSchema = nestedSchema;
        this.typeInfo = typeInfo;
        this.runtimeConverter = runtimeConverter;
    }

    @Override
    public void open(InitializationContext context) throws Exception {
        this.nestedSchema.open(context);
    }

    @Override
    public RowData deserialize(@Nullable byte[] message) throws IOException {
        if (message == null) {
            return null;
        }
        try {
            GenericRecord deserialize = nestedSchema.deserialize(message);
            return (RowData) runtimeConverter.convert(deserialize);
        } catch (Exception e) {
            throw new IOException("Failed to deserialize Avro record.", e);
        }
    }

    @Override
    public boolean isEndOfStream(RowData nextElement) {
        return false;
    }

    @Override
    public TypeInformation<RowData> getProducedType() {
        return typeInfo;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        AvroRowDataDeserializationSchema that = (AvroRowDataDeserializationSchema) o;
        return nestedSchema.equals(that.nestedSchema) && typeInfo.equals(that.typeInfo);
    }

    @Override
    public int hashCode() {
        return Objects.hash(nestedSchema, typeInfo);
    }
}
